Commercial liquid coating compositions are available. Many of these coating compositions are not suitable for coating polycarbonate articles since they are not compatible with the polycarbonate. Also, the uncured coating may adversely affect the polycarbonate article by stress cracking and crazing it, by causing crack propogation into the polycarbonate as a result of brittleness of the coating itself and/or by reducing the properties of the polymer generally such as, for example, impact resistance, elongation, tensile strength and so on. Further, several coatings while compatible with the polycarbonate have little or no chemical barrier properties and/or poor adhesion.
Therefore, a successful coating for polycarbonate articles must be compatible with the polycarbonate and provide barrier or other desirable surface properties while maintaining mechanical or other properties of the polymer substrate and themselves provide chemically resistant surfaces. Also, the cured coating, in this particular application, should particularly provide the coated polycarbonate article with anti-skid properties in addition to the chemical barrier properties necessary to prevent crazing of the substrate polycarbonate in chemically aggressive environments and have improved adhesion to the polycarbonate substrate.
U.S. Pat. No. 4,082,891 discloses photocurable compositions suitable for coatings comprising a polythiol and two different polyenes and polycarbonate articles coated therewith. The instant invention provides coating compositions having good anti-skid properties and good adhesion to a polycarbonate substrate.